2 Unix SMB/CIFS implementation.
4 trivial database library
6 Copyright (C) Andrew Tridgell 1999-2005
7 Copyright (C) Paul `Rusty' Russell 2000
8 Copyright (C) Jeremy Allison 2000-2003
10 ** NOTE! The following LGPL license applies to the tdb
11 ** library. This does NOT imply that all of Samba is released
14 This library is free software; you can redistribute it and/or
15 modify it under the terms of the GNU Lesser General Public
16 License as published by the Free Software Foundation; either
17 version 2 of the License, or (at your option) any later version.
19 This library is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 Lesser General Public License for more details.
24 You should have received a copy of the GNU Lesser General Public
25 License along with this library; if not, write to the Free Software
26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
29 #include "tdb_private.h"
31 /* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
32 static struct tdb_context *tdbs = NULL;
35 /* This is based on the hash algorithm from gdbm */
36 static unsigned int default_tdb_hash(TDB_DATA *key)
38 u32 value; /* Used to compute the hash value. */
39 u32 i; /* Used to cycle through random values. */
41 /* Set the initial value from the key size. */
42 for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++)
43 value = (value + (key->dptr[i] << (i*5 % 24)));
45 return (1103515243 * value + 12345);
49 /* initialise a new database with a specified hash size */
50 static int tdb_new_database(struct tdb_context *tdb, int hash_size)
52 struct tdb_header *newdb;
55 /* We make it up in memory, then write it out if not internal */
56 size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
57 if (!(newdb = calloc(size, 1)))
58 return TDB_ERRCODE(TDB_ERR_OOM, -1);
60 /* Fill in the header */
61 newdb->version = TDB_VERSION;
62 newdb->hash_size = hash_size;
63 if (tdb->flags & TDB_INTERNAL) {
65 tdb->map_ptr = (char *)newdb;
66 memcpy(&tdb->header, newdb, sizeof(tdb->header));
67 /* Convert the `ondisk' version if asked. */
71 if (lseek(tdb->fd, 0, SEEK_SET) == -1)
74 if (ftruncate(tdb->fd, 0) == -1)
77 /* This creates an endian-converted header, as if read from disk */
79 memcpy(&tdb->header, newdb, sizeof(tdb->header));
80 /* Don't endian-convert the magic food! */
81 memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
82 if (write(tdb->fd, newdb, size) != size) {
95 static int tdb_already_open(dev_t device,
98 struct tdb_context *i;
100 for (i = tdbs; i; i = i->next) {
101 if (i->device == device && i->inode == ino) {
109 /* open the database, creating it if necessary
111 The open_flags and mode are passed straight to the open call on the
112 database file. A flags value of O_WRONLY is invalid. The hash size
113 is advisory, use zero for a default value.
115 Return is NULL on error, in which case errno is also set. Don't
116 try to call tdb_error or tdb_errname, just do strerror(errno).
118 @param name may be NULL for internal databases. */
119 struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
120 int open_flags, mode_t mode)
122 return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL, NULL);
125 /* a default logging function */
126 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
127 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
132 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
133 int open_flags, mode_t mode,
134 tdb_log_func log_fn, void *log_private,
135 tdb_hash_func hash_fn)
137 struct tdb_context *tdb;
139 int rev = 0, locked = 0;
143 if (!(tdb = calloc(1, sizeof *tdb))) {
152 tdb->flags = tdb_flags;
153 tdb->open_flags = open_flags;
154 tdb->log_fn = log_fn?log_fn:null_log_fn;
155 tdb->log_private = log_fn?log_private:NULL;
156 tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash;
158 /* cache the page size */
159 tdb->page_size = getpagesize();
160 if (tdb->page_size <= 0) {
161 tdb->page_size = 0x2000;
164 if ((open_flags & O_ACCMODE) == O_WRONLY) {
165 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",
172 hash_size = DEFAULT_HASH_SIZE;
173 if ((open_flags & O_ACCMODE) == O_RDONLY) {
175 /* read only databases don't do locking or clear if first */
176 tdb->flags |= TDB_NOLOCK;
177 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
180 /* internal databases don't mmap or lock, and start off cleared */
181 if (tdb->flags & TDB_INTERNAL) {
182 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
183 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
184 if (tdb_new_database(tdb, hash_size) != 0) {
185 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));
191 if ((tdb->fd = open(name, open_flags, mode)) == -1) {
192 TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",
193 name, strerror(errno)));
194 goto fail; /* errno set by open(2) */
197 /* ensure there is only one process initialising at once */
198 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0) == -1) {
199 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
200 name, strerror(errno)));
201 goto fail; /* errno set by tdb_brlock */
204 /* we need to zero database if we are the only one with it open */
205 if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
206 (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0) == 0))) {
207 open_flags |= O_CREAT;
208 if (ftruncate(tdb->fd, 0) == -1) {
209 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
210 "failed to truncate %s: %s\n",
211 name, strerror(errno)));
212 goto fail; /* errno set by ftruncate */
216 if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
217 || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0
218 || (tdb->header.version != TDB_VERSION
219 && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) {
220 /* its not a valid database - possibly initialise it */
221 if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) {
222 errno = EIO; /* ie bad format or something */
225 rev = (tdb->flags & TDB_CONVERT);
227 vp = (unsigned char *)&tdb->header.version;
228 vertest = (((u32)vp[0]) << 24) | (((u32)vp[1]) << 16) |
229 (((u32)vp[2]) << 8) | (u32)vp[3];
230 tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;
232 tdb->flags &= ~TDB_CONVERT;
234 tdb->flags |= TDB_CONVERT;
235 tdb_convert(&tdb->header, sizeof(tdb->header));
237 if (fstat(tdb->fd, &st) == -1)
240 if (tdb->header.rwlocks != 0) {
241 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
245 /* Is it already in the open list? If so, fail. */
246 if (tdb_already_open(st.st_dev, st.st_ino)) {
247 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
248 "%s (%d,%d) is already open in this process\n",
249 name, (int)st.st_dev, (int)st.st_ino));
254 if (!(tdb->name = (char *)strdup(name))) {
259 tdb->map_size = st.st_size;
260 tdb->device = st.st_dev;
261 tdb->inode = st.st_ino;
262 tdb->locked = calloc(tdb->header.hash_size+1, sizeof(tdb->locked[0]));
264 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
265 "failed to allocate lock structure for %s\n",
272 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0) == -1) {
273 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
274 "failed to take ACTIVE_LOCK on %s: %s\n",
275 name, strerror(errno)));
281 /* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
282 we didn't get the initial exclusive lock as we need to let all other
283 users know we're using it. */
285 if (tdb_flags & TDB_CLEAR_IF_FIRST) {
286 /* leave this lock in place to indicate it's in use */
287 if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0) == -1)
291 /* if needed, run recovery */
292 if (tdb_transaction_recover(tdb) == -1) {
297 /* Internal (memory-only) databases skip all the code above to
298 * do with disk files, and resume here by releasing their
299 * global lock and hooking into the active list. */
300 if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0) == -1)
307 { int save_errno = errno;
313 if (tdb->flags & TDB_INTERNAL)
314 SAFE_FREE(tdb->map_ptr);
318 SAFE_FREE(tdb->name);
320 if (close(tdb->fd) != 0)
321 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
322 SAFE_FREE(tdb->locked);
332 * @returns -1 for error; 0 for success.
334 int tdb_close(struct tdb_context *tdb)
336 struct tdb_context **i;
339 if (tdb->transaction) {
340 tdb_transaction_cancel(tdb);
344 if (tdb->flags & TDB_INTERNAL)
345 SAFE_FREE(tdb->map_ptr);
349 SAFE_FREE(tdb->name);
351 ret = close(tdb->fd);
352 SAFE_FREE(tdb->locked);
354 /* Remove from contexts list */
355 for (i = &tdbs; *i; i = &(*i)->next) {
362 memset(tdb, 0, sizeof(*tdb));
368 /* register a loging function */
369 void tdb_logging_function(struct tdb_context *tdb, tdb_log_func log_fn, void *log_private)
371 tdb->log_fn = log_fn?log_fn:null_log_fn;
372 tdb->log_private = log_fn?log_private:NULL;
375 void *tdb_logging_private(struct tdb_context *tdb)
377 return tdb->log_private;
380 /* reopen a tdb - this can be used after a fork to ensure that we have an independent
381 seek pointer from our parent and to re-establish locks */
382 int tdb_reopen(struct tdb_context *tdb)
386 if (tdb->flags & TDB_INTERNAL) {
387 return 0; /* Nothing to do. */
390 if (tdb->num_locks != 0) {
391 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
395 if (tdb->transaction != 0) {
396 TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));
400 if (tdb_munmap(tdb) != 0) {
401 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));
404 if (close(tdb->fd) != 0)
405 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n"));
406 tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0);
408 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
411 if ((tdb->flags & TDB_CLEAR_IF_FIRST) &&
412 (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0) == -1)) {
413 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
416 if (fstat(tdb->fd, &st) != 0) {
417 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
420 if (st.st_ino != tdb->inode || st.st_dev != tdb->device) {
421 TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n"));
433 /* reopen all tdb's */
434 int tdb_reopen_all(int parent_longlived)
436 struct tdb_context *tdb;
438 for (tdb=tdbs; tdb; tdb = tdb->next) {
440 * If the parent is longlived (ie. a
441 * parent daemon architecture), we know
442 * it will keep it's active lock on a
443 * tdb opened with CLEAR_IF_FIRST. Thus
444 * for child processes we don't have to
445 * add an active lock. This is essential
446 * to improve performance on systems that
447 * keep POSIX locks as a non-scalable data
448 * structure in the kernel.
450 if (parent_longlived) {
451 /* Ensure no clear-if-first. */
452 tdb->flags &= ~TDB_CLEAR_IF_FIRST;
455 if (tdb_reopen(tdb) != 0)